Managing Scylladb

ScyllaDB Management Skill

Monitor, analyze, and optimize ScyllaDB clusters safely.

MANDATORY: Discovery-First Pattern

Always check cluster status and list keyspaces before any CQL operations. Never assume keyspace or table names.

Phase 1: Discovery

#!/bin/bash

SCYLLA_HOST="${SCYLLADB_HOST:-localhost}"
SCYLLA_PORT="${SCYLLADB_PORT:-9042}"

echo "=== Cluster Status ==="
nodetool -h "$SCYLLA_HOST" status

echo ""
echo "=== Scylla Version ==="
nodetool -h "$SCYLLA_HOST" version

echo ""
echo "=== Keyspaces ==="
cqlsh "$SCYLLA_HOST" "$SCYLLA_PORT" -e "DESCRIBE KEYSPACES;"

echo ""
echo "=== Cluster Description ==="
nodetool -h "$SCYLLA_HOST" describecluster

echo ""
echo "=== Shard Info ==="
curl -s "http://$SCYLLA_HOST:10000/system/uptime_ms" 2>/dev/null
curl -s "http://$SCYLLA_HOST:10000/storage_service/hostid/local" 2>/dev/null

Phase 1 outputs: Node states, Scylla version, keyspace list, cluster topology, shard count.

Phase 2: Analysis

#!/bin/bash

SCYLLA_HOST="${SCYLLADB_HOST:-localhost}"
KEYSPACE="${1:-my_keyspace}"

echo "=== Keyspace Details ==="
cqlsh "$SCYLLA_HOST" -e "DESCRIBE KEYSPACE $KEYSPACE;"

echo ""
echo "=== Table Stats ==="
nodetool -h "$SCYLLA_HOST" tablestats "$KEYSPACE" | grep -E "Table:|Space used|Number of|Compaction|Read Latency|Write Latency" | head -30

echo ""
echo "=== Compaction Stats ==="
nodetool -h "$SCYLLA_HOST" compactionstats

echo ""
echo "=== Scheduling Groups (Workload Prioritization) ==="
curl -s "http://$SCYLLA_HOST:10000/task_manager/list_module_tasks/compaction" 2>/dev/null | head -10

echo ""
echo "=== Repair Status ==="
nodetool -h "$SCYLLA_HOST" repair_status 2>/dev/null || \
    nodetool -h "$SCYLLA_HOST" netstats | grep -A5 "Repair"

echo ""
echo "=== Thread Pool Stats ==="
nodetool -h "$SCYLLA_HOST" tpstats | head -25

Output Format

SCYLLADB ANALYSIS
=================
Cluster: [name] | Nodes: [count] | Version: [version]
Keyspaces: [count] | Shards/Node: [count]

ISSUES FOUND:
- [issue with affected keyspace/node]

RECOMMENDATIONS:
- [actionable recommendation]

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations